The statistics are startling. Viewers across the globe have switched on Big Brother more than 18 billion times and 1 billion votes have been cast for the multinational cast lists. The programme is, says Peter Bazalgette, "the most perfectly converged piece of entertainment ever conceived" - bringing together television, telephony and the internet. In short, welcome to the future.

Billion Dollar Game is the story not of one programme but of three: it also takes in Who Wants to Be a Millionaire? and Survivor, arguing they are the programmes that changed the face of television. They did so because their creators took huge creative and business risks; but with high stakes came high rewards. Survivor's Charlie Parsons is now said to be disenchanted with the world of television, but this is cushioned by what Bazalgette estimates to be £10m a year earned from his continuing productions. This is a rattling good business story as well as a tale from medialand.

The strength of the narrative is twofold. First, it recognises that nothing is entirely new in television. Practical jokes on unsuspecting televised victims date back to Candid Camera in 1948; a BBC play in the 1960s imagined 24-hour camera surveillance with individuals put under pressure by performing tasks; and The Family was a reality TV hit in the early 70s. Bazalgette guides us through the way European television synthesised these genres with John De Mol as a key innovator, and there is enough detail to equip Mastermind contestants for a specialist round on Dutch television formats of the 80s.

The second strength of the book is that it gives the clearest account I've yet come across of the way the media revolution has changed content as well as format. The internet gave us phenomena such as the Jennicam - Jennifer Ringley's webcam allowing voyeurs anywhere in the world to see her performing what we should politely call a range of human functions. Multichannel offered endless airtime and a greater imperative to make a splash with audacious programming. Interactive television sharpened the incentive to allow viewers to make a choice about what should happen next, and pressing the red button became a vital accessory. Most importantly, it all came together in a business model: subscription access to the internet, premium rate lines to cast the votes - and, of course, a global media market which paid big bucks for successful formats.

It did still need at its heart a television show that worked. Bazalgette gives a good account of the birth of Millionaire - originally called Cash Mountain. It was initially rejected by ITV but the triumph was in the detail. Its producers, the UK independent Celador, changed almost everything in the two weeks before it was launched. The initial theme tune - "an oppressively jolly jingly pop song" - was ditched. The lighting was made darker and more dramatic, and more cameras were brought in to show emotions close-up. This template was later rolled out worldwide. But the significance of Millionaire was the way it used phone charges to pay for its prizes: the million-pound giveaway was only possible because viewers effectively paid to enter, and the big prize and the drama of getting to it prompted hundreds of thousands of calls each night.

It would take a heart of stone not to enjoy some of the best moments of Millionaire. But Big Brother was always more controversial. Bazalgette launched the British version, and he gleefully retails some of the condemnation of the critics while noting that they were predominantly male and over 50. "Men," he writes, "have little sympathy for soap operas with emotional storylines." And that points to his vision of Big Brother: not reality television, but candidly "an entertainment, a pantomime". He ties this in with the way the media need a constant fresh supply of celebrities - so they create them from shows such as Big Brother, and we draw closer than ever to Andy Warhol's promise of 15 minutes of fame for everyone.

Like it or not, we are in an age of unrestricted digital media and Bazalgette reports fairly on the way Big Brother has spread across the globe, usually triumphing over those who want to restrict it - though it did fall foul of Islamic sensibilities in its Middle East version. And it's here one feels a twinge of sympathy for King Canute. Should a globalised media erode genuinely held beliefs, and what downsides are there are to "perfect convergence"? It takes nothing away from this spirited and interesting book to wonder whether this union of new media and new money has produced an unalloyed good. The question is simple: is this the best we can do?